MODL-09. IMAGE-BASED SCREENING IN MEDULLOBLASTOMA REVEALS TUMOR-SUPPRESSIVE EFFECTS OF THE NEUROPROTECTIVE AGENT URMC-12K

Abstract

Abstract BACKGROUND Enhanced motility and the invasive behavior of medulloblastoma (MB) influence microenvironment interactions and may promote distant spread. Current drug screening focuses on cytotoxic agents, leaving subtle but potentially therapeutically relevant drug phenotypes associated with motility and invasiveness unrecognized. The serine/threonine kinase MAP4K4 is upregulated in MB and promotes invasiveness1,2. Toxicities associated with existing MAP4K4 inhibitors in the CNS prevented further pre-clinical evaluation. URMC-12k is a novel MAP4K inhibitor identified as a motor-neuron-protective agent in ALS. Using advanced imaging approaches, we investigated URMC-12k as a tumor-suppressive drug in MB and characterized its effects at the molecular, cellular, and tissue levels. METHODS We use cell-based 3D invasion assays and quantitative microscopy to assess tumor-restraining activities of URMC-12k, and machine learning to detect URMC-12k phenotypes associated with repressed motility. We use tissue and zebrafish larval models to explore URMC-12k effects on cell and tissue viability and anti-invasion efficacy. We determined URMC-12k targets in MB cells using phosphoproteomics. RESULTS URMC-12k outcompetes existing MAP4K4 inhibitors in repressing basal and growth-factor-induced matrix invasion with no detectable effects on vertebrate developmental processes. A computational model trained to detect morphological alterations in the actin cytoskeleton associated with cell dynamics established a firm correlation between the URMC-12k-repressed motile behavior and alterations in the tumor cell actin cytoskeleton. Quantitative imaging further revealed that URMC-12k promoted increased cell clustering and reduced deposition of extracellular vesicles. Phosphoproteomics identified proteins involved in cell adhesion organization and vesicle trafficking as potential molecular effectors targeted by URMC-12k. CONCLUSIONS URMC-12k effectively inhibits MB cell migration and displays no toxicities at effective concentrations. The regulation of cell-cell adhesion molecules and the deposition of extracellular vesicles revealed by URMC-12k are tumor-promoting, druggable mechanisms of MAP4Ks in MB. 1. 1Migliavacca, J., et al. Commun Biol5, (2022). 2. 2Tripolitsioti, D. et al. Oncotarget9, 23220–23236 (2018).